第一肋骨奇形による胸郭出口症候群の1例—症例報告と文献的考察

Thoracic Outlet Syndrome due to First Rib Anomaly:A case report

I．はじめに

　胸郭出口症候群Thoracic outlet syndrome（以下TOS）の原因としては頸肋，前斜角筋によるものが一般的であり，第一肋骨の異常によるものは十分に知られていない^3,5,8,11）．最近われわれは，特異な第一肋骨奇形が原因でTOSを呈した症例を経験したので若干の考察を加えて報告する．

Compared to cervical rib, first rib anomaly is less familiar to us as a cause of thoracic outlet syndrome. We report a case of thoracic outlet syndrome clue to first rib anomaly.

A 50-year-old man was admitted to our hospital be-cause of right arm pain when his arm was raised up. Chest X-ray showed an abnormal right first rib which made a J-shaped curve and was attached to the second rib. A palpable mass was noted in the supraclavicular region. Angiography revealed complete occlusion of the right subclavian artery in the Allen test position. Dur-ing conservative therapy for two months, the symptom was gradually getting worse. We performed resection of the right first rib and anterior scalenotomy by the supraclavicular approach. The patient made a good re-covery after the surgery. Postoperative angiogram showed no stenotic lesion of the right subclavian artery.

If a patient has complaints suggesting compression of the subclavian neurovascular bundle, we should he careful not to overlook the first rib anomaly on chest X-ray.